10/31/2007. Remarks by Johan Visschedijk: "The fourth BO 105 was produced by Messerschmidt-Bölkow GmbH and first flown on May 1, 1969, fourteen days before the merger with Blohm to become MBB. Fitted with two 317 shp Allison 250-C18 turboshaft engines it was used for type certification. Subsequently it was fitted with two 400 shp 250-C20 engines, with which it flew for the first time on January 11, 1971. In this configuration it was used as a test aircraft for the BO 105P PAH (Panzer Abwehr Hubschrauber, Anti-Tank Helicopter) to be built for the German Army.

In 1973 it was converted to the BO 105HGH (Hoghgeschwindigkeits-Hubschrauber, High Speed Helicopter, as shown in the picture above) fitted with a high-speed shrouded rotor hub, faired rear fuselage, four-leg landing gear and flew for the first time in the autumn of 1973, attaining a speed of 200 knots (230 mph, 370 kmh) in a shallow dive. Note the tufted fuselage, tail and fins.

After fitting of wings, spanning 19 ft 8.25 in (6.0 m), and new tapered rotor blades, flight testing was resumed in 1974. Pilots Willy Sommer and Hans Glöckl achieved a maximum speed of 218 knots (251 mph, 404 kmh) with a rotor tip speed of Mach 0.97, during the HGH's last flight on March 4, 1975.

Converted to a normal configuration the helicopter was used for additional rotor testing and finally donated to the Deutsches Museum, München in late 1979."